The Integrated Human-Earth System Dynamics (IHESD) scientific focus area (SFA) aims to improve our integrated understanding of the long-term co-evolution of the coupled human-Earth systems, and their complex interactions. Its vision is to deliver the next generation of scientific advances through next-generation, community human-Earth modeling and research that will flexibly address emerging issues at the intersection of energy, water, land, the economy, and the environment at continental to global scales, and at resolutions that permit robust scenario exploration and uncertainty characterization. IHESD models provide unique insights into the behavior of human systems at global scales and into how those systems both influence and are influenced by the Earth system. IHESD research specializes in capturing the emergent behavior produced by the complex interactions among different sectors and regions. It incorporates insights from disciplinary models and studies but does not seek to reproduce the level of detail seen in disciplinary science.

This SFA has also supported the development and use of the Global Change Assessment Model (GCAM), the world’s premier open-source integrated human-Earth model since its inception more than three decades ago. GCAM has made critical contributions to our understanding of how energy technologies, land-use practices, and other human activities influence Earth system dynamics, and has been the foundation for developing plausible future scenarios that are used in science-based environmental and energy assessments. The complexity of GCAM has evolved commensurate with scientific questions about how human and Earth systems interact. In particular, the IHESD team’s focus has shifted from studying the interactions of a limited number of systems (energy-economy-climate) at a highly-aggregated level to consideration of multiple interactions (energy-water-land-economy-climate) at greater temporal, spatial, and process resolution, though still in a global context.